Graphite-titanium-nanocomposite complex and method of preparation thereof

ABSTRACT

A 3D structure of the graphite-titanium-nanocomposite complex and a method of preparing the graphite-titanium-nanocomposite complex are disclosed. The Graphite-titanium-nanocomposite complex includes a metal core associated with the two phases, amine functionalized graphite, and amine functionalized titanium. The method of preparation includes amine functionalizing of graphite and titanium with coupling agents to produce amine functionalized titanium and graphite, further mixing with a metal ion solution for synthesizing an ion complex. Trisodium citrate solution and sodium borohydride solution is added to the ion complex to prepare a 3D structure of the graphite-titanium-nanocomposite complex, employed as a catalyst.

FIELD OF INVENTION

The present disclosure generally relates to a field of Graphite-titanium nanocomposites. More specifically, the invention relates to a Graphite-titanium-nanocomposite complex and a method of preparation thereof.

BACKGROUND OF INVENTION

Titanium dioxide and Graphite have been employed in numerous applications like a solar cell, semiconductors, communication, bio-sensors, photovoltaic, photocatalytic, energy storage, etc., owing it to the properties such as conductivity, electro-chemical, etc. However, the erstwhile methods of preparation of titanium-Graphite nanocomposites involve methods like physical mixing, hydrothermal, sonochemical, etc. wherein the interaction between Graphite and titanium is weak due to the absence of a chemical bonding between the two phases of Graphite and titanium. Furthermore, physical mixing for instance involves disadvantageous side effects like cracking, unstable structures, other structural defects, etc. thereby making it an unsuitable method of preparation of nanocomposites.

Therefore, there exists a need for a method of preparation of titanium-Graphite nanocomposites rendering improved structural properties and efficiency over the erstwhile existing nanocomposites.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the invention.

FIGS. 1a, 1b, 1c and 1d are illustrative of SEM images alongside EDX images of mono-amine-TiO₂, mono-amine-Graphite, TiO₂-mono-amine-Cu-mono-amine-Graphite and TiO₂-di-amine-Cu-di-amine-Graphite.

FIGS. 2a, 2b, 2c and 2d are illustrative of XRD diffractogram for titanium-amine, Graphite-amine, TiO₂-mono-amine-Cu-mono-amine-Graphite and TiO₂-di-amine-Cu-di-amine-Graphite respectively.

FIGS. 3a, 3b, 3c and 3d are illustrative of thermogravimetric analysis curves of mono-amine-TiO₂, di-amine-TiO₂, mono-amine-Graphite and Di-amine-Graphite.

FIG. 4 illustrates the absorbance studies of di-amine-titanium-Cu-di-amine-Graphite, mono-amine-titanium-Cu-mono-amine-Graphite, TiO₂ and Graphite when employed as catalysts in a degradation reaction of an organic pollutant.

FIGS. 5a and 5b are illustrative of structures of Mono-amine-Graphite-Cu-mono-amine-titanium and Mono-amine-Graphite-Cu(Nanoparticle)-mono-amine-titanium respectively.

FIGS. 6a and 6b are illustrative of structures of Di-amine-Graphite-Cu-Di-amine-titanium and Di-amine-Graphite-Cu(Nanoparticle)-Di-amine-titanium respectively.

FIGS. 7a and 7b are illustrative of XRD diffractogram for TiO₂-(mono-amine)-Cu-nanoparticle-Mono-amine-Graphite and TiO₂-(Di-amine)-Cu-Nanoparticle-Di-amine-Graphite respectively.

DETAILED DESCRIPTION

Before describing in detail embodiments that are in accordance with the invention, it should be observed that the embodiments reside primarily in a Graphite-titanium nanocomposite complex comprising a 3D structure of metal ions/metal nanoparticles forming a complex between Graphite and titanium and a method of preparation thereof. The method of preparation includes chemical complexation to produce the Graphite-titanium nanocomposite complex.

In this document, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article or composition that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article or composition. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article or composition that comprises the element.

Various embodiments of the invention provide a Graphite-titanium-nanocomposite complex and a method of preparation thereof.

In accordance with the present invention, a Graphite-titanium-nanoparticle complex includes a metal core associated with a nanoparticle, an amine functionalized Graphite and an amine functionalized titanium, wherein the metal core, the nanoparticle, the amine functionalized Graphite and amine functionalized titanium, together form a solid 3D structure. The 3D structure of the Graphite-titanium-nanocomposite complex includes an electron snaring mechanism by virtue of the metal ion binding with Graphite and titanium, thereby improving the photocatalytic properties of the Graphite-titanium nanocomposite complex. A coordinate covalent bond existing between the metal ion and functional groups of Graphite and titanium holds the 3D structure together.

In another embodiment, a thiol derivative functionalized Graphite and a thiol derivative functionalized titanium along with the metal core and the nanoparticle, together form a solid 3D structure. Any functional group constituting a coupling agent capable of forming a ligand with metals may also be employed for functionalizing Graphite and titanium.

In yet another embodiment, other allotropes and forms of graphite/carbon including, but not limited to graphene, C60 and mesoporous carbon, is employed in forming a nanoparticle complex along with titanium. Metal oxides including, but not limited to, silica, MgO and ZnO are employed in forming the nanoparticle complex along with graphite.

Characterization studies of the Graphite-titanium-nanocomposite complex include SEM images alongside the EDX analysis images represented by FIGS. 1a, 1b, 1c and 1d , for mono-amine-TiO₂, mono-amine-Graphite, TiO₂-mono-amine-Cu-mono-amine-Graphite and TiO₂-di-amine-Cu-di-amine-Graphite respectively. Mono-amine-TiO₂, mono-amine-Graphite, TiO2-mono-amine-Cu-mono-amine-Graphite and TiO₂-di-amine-Cu-di-amine-Graphite are products formed at different stages of a method of preparation of Graphite-titanium-nanocomposite complex. FIG. 1a is representative of the morphology of mono-amine-TiO₂, the spherical particles of mono-amine-TiO₂ measuring in the range of 100 nm. The EDX peaks of Ti at 0.45 (Lα), 4.5 (Kα) and at 0.4 (Kα) are representative of oxygen, thereby confirmative of the presence of Titanium dioxide. FIG. 1b is representative of the leaf-like morphology of mono-amine-Graphite. FIG. 1c , representative of the morphology of TiO2-mono-amine-Cu-mono-amine-Graphite, includes the spherical shape of titanium as well as the leaf-like morphology of Graphite. Furthermore, the shiny nanoparticles are representative of CuO nanoparticles embedded between layers of the nanocomplex. The EDX peaks of FIG. 1c , specifically, peaks at 0.27 KeV refer to graphite, peaks at 0.454.5 KeV (Lα) refer to titanium and peaks at 1.7 KeV (Kα) refer to silica as well as oxygen. Also, the peaks at 0.930 and 8.0 KeV refer to Cu (Kα) and (Lα) respectively.

FIG. 1d represents the morphology of TiO₂-di-amine-Cu-di-amine-Graphite, indicating a mixed distribution of the two phases, namely TiO₂ and Graphite based on the difference in contrast intensity of the phases. The EDX peaks of FIG. 1d at 0.27, 0.45, 0.52, 0.93, 1.73, 4.5 and 8.0 KeV are indicative of the presence of TiO₂, Graphite, silane coupling agent and copper.

FIG. 2a represents the XRD diffractogram of pure titanium, pure titanium being in an Anatase phase. FIG. 2b represents the XRD diffractogram of amine functionalized Graphite, the presence of peaks at 22.5, 37.5, 48.5, 55.0, 76 and at 83 2θ in FIGS. 2c and 2d , are representative of the two phases together (titanium and graphite) after chemical binding, along with low-intensity Cu peaks. The low-intensity Cu peaks is evidential of less than 3% of copper in the nanocomplex.

FIGS. 3a, 3b, 3c . and 3 d are representative of the thermogravimetric analysis curves of mono-amine-TiO₂, di-amine-TiO₂, mono-amine-Graphite and Di-amine-Graphite, thereby indicative of the organic content. The organic content in mono-amine-TiO₂ and di-amine-TiO₂ is approximately 15% and 20% respectively. Similarly, the organic content in mono-amine-Graphite and Di-amine-Graphite is 8.6% and 10.92% respectively. Higher organic content in TiO₂ as compared to graphite is due to the higher surface area of TiO₂ as opposed to Graphite.

Hereinafter, a method of preparing the Graphite-titanium-nanocomposite complex is described.

The method of preparation begins with activating a graphite powder surface using HNO₃ and H₂SO₄, used in a mass ratio of 1:1. Graphite powder is mixed with HNO₃ and H₂SO₄ in a round-bottomed flask overnight at temperature of 80° C. followed by rinsing with deionized water to be eventually dried at 100° C. Activating the graphite powder surface leads to abundant formation of hydroxy and carboxy groups, thereby leading to ease of association of a coupling agent in an ensuing step. Activated graphite powder and titanium undergoes amine functionalizing by a coupling agent in a round-bottom flask fitted with a reflux condenser, the reaction occurring under a noble gas atmosphere for a time period of six hours, followed by cooling down at room temperature. In a preferred embodiment, the noble gas atmosphere is an argon atmosphere. The product of the reaction, a dried form of amine functionalized Graphite and amine functionalized titanium is separated by centrifuging, rinsing thoroughly with toluene and methanol and drying overnight under vacuum. In the next step, mixing of the amine functionalized Graphite with the amine functionalized titanium occurs in a mass ratio of 1:1, in a vortex shaker to produce a mixture. Furthermore, the method includes synthesizing an ion complex by adding an ethanolic solution of a metal ion by shaking the mixture and metal ion solution at a temperature of 80° C. for a time period ranging between twelve to thirty-six hours. Thereafter, freshly prepared trisodium citrate solution and sodium borohydride solution in a mass ratio of 1:1 is added to the ion complex in a shaker for a time period of an hour at room temperature to produce a Graphite-titanium-nanoparticle complex.

In another embodiment, the ethanolic solution of a metal ion to synthesize an ion complex is selected from other metal ions namely Ag, Au, Co, Cd, Ni, Ru, Rh, etc. The selection of the metal ion is based on the binding energy between the metal ion and a functional group to prepare a solid and stable nanoparticle complex and to further control the characteristics of the complex such as charge transport, stability and paramagnetic properties.

The coupling agents are selected from a group of silane coupling agents. In a preferred embodiment, silane coupling agents are selected from a group of 3-Aminepropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl] ethylenediamine.

Accordingly, in one embodiment, Graphite and titanium undergoes amine functionalizing by the coupling agent 3-Aminepropyltrimethoxysilane. The sharp EDX peaks of carbon in FIG. 1b at around 0.27 KeV for (Kα) confirms the presence of graphite. Furthermore, the silica peak at 1.7 KeV (Kα) and 0.525 KeV confirms the attachment of the silane coupling agent 3-Aminepropyltrimethoxysilane to the surface of graphite. In an example, 2 g of TiO₂ and Graphite is dispersed by agitation at a rising temperature up to 80° C., in 100 ml of dry toluene contained in a 250 ml round-bottom flask fitted with a reflux condenser. In the ensuing step, 3 ml of the coupling agent 3-Aminepropyltrimethoxysilane is slowly added to the round-bottom flask, the reaction occurring in an argon atmosphere for a period of six hours and further cooled down to room temperature. The reaction involving chemical immobilization produces mono-amine-Graphite and mono-amine-titanium. The products mono-amine-Graphite and mono-amine-titanium are separated by centrifuging, rinsing thoroughly with toluene and methanol and finally dried overnight under vacuum to produce dried forms of the products. 100 mg each of mono-amine-Graphite and mono-amine-titanium (mass ratio of 1:1) are mixed together in a vortex shaker and 5 ml of an ethanolic solution of copper(II) acetate hydrate is added to the mixture of mono-amine-Graphite and mono-amine-titanium, with gentle shaking at a temperature of 80° C. for a time period ranging from twelve to thirty-six hours. The previous step produces an ion complex of mono-amine-Graphite-Cu-mono-amine-titanium as represented in FIG. 5 a.

50 mg of mono-amine-Graphite-Cu-mono-amine-titanium is transferred to a 40 ml glass vial along with 3 ml of freshly prepared trisodium citrate and 3 ml of 0.1 M sodium borohydride solution, the glass vial is further left in a shaker for an hour at room temperature. The glass vial undergoes centrifuging, rinsing with degassed deionized water and is dried under vacuum in desiccator to produce mono-amine-Graphite-Cu(Nanoparticle)-mono-amine-titanium as represented in FIG. 5 b.

In another embodiment, Graphite and titanium undergo amine functionalizing by the coupling agent N-[3-(trimethoxysilyl)propyl] ethylenediamine. In an example, 2 g of TiO₂ and 2 g of Graphite is dispersed by agitation at a rising temperature up to 80° C., in 100 ml of dry toluene contained in a 250 ml round-bottom flask fitted with a reflux condenser. In the ensuing step, 3 ml of the coupling agent N-[3-(trimethoxysilyl)propyl] ethylenediamine is slowly added to the round-bottom flask, the reaction occurring in a noble gas atmosphere for a period of six hours and further cooled down to room temperature. The reaction involving chemical immobilization produces di-amine-Graphite and di-amine-titanium. The products di-amine-Graphite and di-amine-titanium are separated by centrifuging, rinsing thoroughly with toluene and methanol and finally dried overnight under vacuum to produce dried forms of the products. 100 mg each of di-amine-Graphite and di-amine-titanium (mass ratio of 1:1) are mixed together in a vortex shaker and 5 ml of an ethanolic solution of copper(II) acetate hydrate is added to the mixture of di-amine-Graphite and di-amine-titanium, with gentle shaking at a temperature of 80° C. for a time period of 36 hours. The previous step produces an ion complex di-amine-Graphite-Cu-di-amine-titanium as represented in FIG. 6 a.

50 mg of di-amine-Graphite-Cu-di-amine-titanium is transferred to a 40 ml glass vial along with 3 ml of freshly prepared trisodium citrate and 3 ml of 0.1 M sodium borohydride solution, the glass vial is further left in a shaker for an hour at room temperature. The glass vial further undergoes centrifuging, rinsing with degassed deionized water and is dried under vacuum in desiccator to produce di-amine-Graphite-Cu(Nanoparticle)-di-amine-titanium as represented in FIG. 6 b.

FIGS. 7a and 7b are illustrative of XRD diffractogram of the two graphite nanocomposite complexes, namely TiO₂-(mono-amine)-Cu-nanoparticle-Mono-amine-Graphite and TiO₂-(Di-amine)-Cu-Nanoparticle-Di-amine-Graphite respectively. New peaks at 32.0, 44.5 and 78.0 are representative of transformation of copper oxide particles to copper nanoparticles in a crystalline phase. FIG. 7b is representative of peaks with a shift, the shift indicative of a geometry effect witnessed in the chemical structure of the nanocomposite complex due to the presence of coupling agent, diamine N-[3-(Trimethoxysilyl)propyl]ethylenediamine.

In another embodiment, the Graphite-titanium-nanocomposite complex is employed as a catalyst in a degradation reaction of an organic pollutant. In an example, Rhodamine B is representative of the organic pollutant. A comparative example is setup using Rhodamine B as the organic pollutant. Further, 50 mg of TiO₂, Graphite, mono-amine-titanium-Cu-mono-amine-Graphite and di-amine-titanium-Cu-di-amine-Graphite each placed separately in four different test tubes as catalysts and 3 ml of 1 mM of Rhodamine B was added to each tube, the four tubes left inside a box. The box was covered from inside using an aluminum foil and a lamp was switched on. After a time period of three hours, the four catalysts were removed by filtration and the clear solution from each test tube was transferred to a 3 ml cuvette for measuring absorbance using a UV-Vis PG Instrument. The results of the absorbance measurements as illustrated in FIG. 4 are representative of the increased efficiency of the mono amine-titanium-Cu-mono-amine-Graphite and di-amine-titanium-Cu-di-amine-Graphite catalysts over titanium and Graphite. Advantageously, the increased efficiency of the ion complexes namely express excellent photocatalytic activity over the erstwhile catalysts by virtue of the chemical complexation reaction involving copper atom/ion attributing electron snaring mechanism to the ion complex. Furthermore, the presence of Graphite and titanium with their inbound properties accentuate the property of charge transference thereby facilitating the increase in efficiency and photocatalytic activity.

In yet another embodiment, the Graphite-titanium-nanocomposite complex is employed as a biosensor in analytical applications.

The Graphite-titanium-nanocomposite complex is also employed as a solar cell in photovoltaic applications. Other applications employing Graphite-titanium-nanocomposite include photodegradation, supercapacitor, and hydrogen evolution.

Those skilled in the art will realize that the above-recognized advantages and other advantages described herein are merely exemplary and are not meant to be a complete rendering of all of the advantages of the various embodiments of the invention.

In the foregoing specification, specific embodiments of the invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued. 

What is claimed is:
 1. A method of preparing a graphite-titanium-nanoparticle complex, the method comprising: amine functionalizing of graphite by a coupling agent to produce amine functionalized graphite, wherein the amine functionalizing occurs in an atmosphere of noble gas for a time period of six hours; amine functionalizing of titanium by a coupling agent to produce amine functionalized titanium, wherein the amine functionalizing occurs in an atmosphere of noble gas for a time period of six hours; mixing the amine functionalized graphite with the amine functionalized titanium using a vortex shaker to produce a mixture, wherein the mass ratio of amine functionalized graphite to amine-functionalized titanium is 1:1; synthesizing an ion complex by adding a metal ion solution to the mixture, the metal ion solution and mixture undergoing gentle shaking at a temperature of 80° C. for a time period ranging from twelve to thirty-six hours; and adding freshly prepared trisodium citrate solution and sodium borohydride solution to the ion complex in a shaker for a time period of one hour at room temperature to produce a graphite-titanium-nanoparticle complex, wherein the mass ratio of trisodium citrate solution to sodium borohydride is 1:1.
 2. The method according to claim 1, wherein amine functionalizing of graphite further comprises separating a dried form of amine functionalized graphite by centrifuging the amine functionalized graphite followed by rinsing with toluene and methanol.
 3. The method according to claim 1, wherein amine functionalizing of titanium further comprises separating a dried form of amine functionalized titanium by centrifuging the amine functionalized titanium followed by rinsing with toluene and methanol.
 4. The method according to claim 1, wherein amine functionalizing occurs in an atmosphere of argon gas for a time period of six hours.
 5. The method according to claim 1, wherein amine functionalizing includes using a coupling agent selected from a group of 3-Aminepropyltrimethoxysilane and N-[3-(trimethoxysilyl)propyl] ethylenediamine.
 6. The method according to claim 1, wherein the amine functionalizing of titanium produces amine functionalized titanium selected from a group of mono-amine-titanium and di-amine titanium.
 7. The method according to claim 1, wherein the amine functionalizing of graphite produces amine functionalized Graphite selected from a group of mono-amine-graphite and di-amine-graphite.
 8. The method according to claim 1, wherein the adding of the metal ion solution comprises adding copper acetate (II) hydrate to the mixture.
 9. The method according to claim 1, wherein the adding of the metal ion solution comprises selecting hydrate solution of metal ions from a group of Ag, Au, Co, Cd, Ni, Ru and Rh.
 10. The method according to claim 1, wherein the graphite-titanium-nanoparticle complex is mono-amine-graphite-Cu(Nanoparticle)-mono-amine-titanium.
 11. The method according to claim 1, wherein the graphite-titanium-nanoparticle complex is graphite-di-amine-Cu(Nanoparticle)-di-amine-titanium. 